Interestingly, I performed this mod today, and my results were different. The check engine light did not come on until the second time I drove it. More importantly, it did not eliminate purges. It DID dramatically increase the time between purges, and they seem to end a bit sooner. The latter may be the placebo effect though. This may be a good thing, as I still have a cat. Regardless, the car is much easier to get higher mileage numbers with, perhaps equal to the hottest weeks of summer.
What value did you use? I am using 1 Mohm which results in a secondary sensor value of .015v. Does your car have 2 or 3 sensors? I watch my primary O2 values closely and see it lock right on .395 - .4v and hold as long as road conditions are appropriate. No purges at all. Could be a ECM revision?? I did have the ECM replaced in 2008 due to a P420 recall which supposedly made the ECM less sensitive to the catalytic converter deterioration.
Disclaimer: I also want to add, I have no idea what affect this 'mod' will have on a catalytic converter, so use it at your own risk. As far as reversal, it is really easy to reverse if you can solder and shrink wrap. Btw, I did all the cuts on the sensor side of the plug which only has 4 wires. Honestly I didn't think of this so much as a mod as a stop gap until I can implement a circuit that will allow the car to run without, or at least minimal purges and no codes.
There you go. My OBDII C&C hasn't arrived yet, so I can't check the voltage. I understand the risks. Near as I figure, if it is still purging a little bit, the cat will be fine.
I did the mod today; didn't work. I didn't get any codes and I got two purges in a 10+ mile test run. Perhaps it's not working because of my 345 ECU?
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Silver '00 MT
90.2 LMPG
80+ psi in RE92's for the past 2 years without incident
Calpod switch
Warm air mod
Grill block
EPS fuse removed
FAS/fuel injector interrupt circuit
grid charger
OBDII C&C gauge
I did the mod today; didn't work. I didn't get any codes and I got two purges in a 10+ mile test run. Perhaps it's not working because of my 345 ECU?
Really weird that you didn't get a code, not even pending? At 1Mohm I will see pending code within one mile, and the code will set within another 10 miles. The purges stop as soon as the pending code is set. This morning, which was the first I used the OBCIIC&C gauge the lean burn light stayed on for 5 miles without a flicker (~22AF ratio). That holds until I either open the throttle more, enter an area that requires more engine load, or it goes into fuel cut.
Not sure on ECU revisions. I'll see if I can pull my ECU rev #
I still get a purge occasionally, but much longer intervals. It also seems to get to lean burn more quickly upon warmup. Really the only downside is the check engine light and that it seems to block auto-stop intermittently.
I still get a purge occasionally, but much longer intervals. It also seems to get to lean burn more quickly upon warmup. Really the only downside is the check engine light and that it seems to block auto-stop intermittently.
Again strange. The only recent issues I have had with autostop has been temperature related. There could be much more going on with ECM revisions than we are aware of.
Btw, my check engine light, the P137 code, occasionally goes off on its own, but stays pending.
Has anyone else tried this or had any luck? I am heading to radio shack tomorrow to pick up a 1000ohm resistor . Do I need an additional resistor for the other two white wires also for the heater circuit side of the plug?
Has anyone else tried this or had any luck? I am heading to radio shack tomorrow to pick up a 1000ohm resistor . Do I need an additional resistor for the other two white wires also for the heater circuit side of the plug?
I'm still running the mod. With winter temps I can easily get into and hold lean burn as long as the engine is above ~150F and intake temps are above ~70F (heated via turbo) and as long as load stays low.
The heater portion of the circuit can be spoofed by using 3 X 50ohm (10 watt) resistors in parallel.
After rereading an earlier post, he said it had two purges in 10 miles, that sounds like the mod is working. Simply dropping out of lean burn doesn't mean a purge occurs and purges typically happen much more often than 2 in 10 miles. Increased load, shifting, or and change in throttle position will cause a drop out of lean burn. The lack of a code is what confuses me. The P137 should show as pending on a code reader within ~1 mile at most, and should set a check engine light within 10 miles.
I want to reiterate, this 'mod' isn't a miracle fix that gives lean burn all the time. It seems that it puts the system into an error state in which lean burn still functions, but disables the ability for the system to enter into purges. You still have to have conditions that normally allow lean burn.
I'm still running the mod. With winter temps I can easily get into and hold lean burn as long as the engine is above ~150F and intake temps are above ~70F (heated via turbo) and as long as load stays low.
The heater portion of the circuit can be spoofed by using 3 X 50ohm (10 watt) resistors in parallel.
After rereading an earlier post, he said it had two purges in 10 miles, that sounds like the mod is working. Simply dropping out of lean burn doesn't mean a purge occurs and purges typically happen much more often than 2 in 10 miles. Increased load, shifting, or and change in throttle position will cause a drop out of lean burn. The lack of a code is what confuses me. The P137 should show as pending on a code reader within ~1 mile at most, and should set a check engine light within 10 miles.
I want to reiterate, this 'mod' isn't a miracle fix that gives lean burn all the time. It seems that it puts the system into an error state in which lean burn still functions, but disables the ability for the system to enter into purges. You still have to have conditions that normally allow lean burn.
Is the heater spoof simply a way to prevent an additional code besides the p0139? Or I guess a better question is what role does the heater spoof play in all this?
I would be tickled pink if I could obtain 10 miles with only 2 purges. I have a scan gauge to track lean burn and also load and throttle position and temps of air intake and water temp. Currently I would estimate a purge cycle every 2 min on average every 2 mins. Never longer than 5 min at a time never shorter and 30 secs between cycles. This of course is flat no wind constant 50mph and constant tps.
Did you ever figure out what ECM revision you have? I have at 2000 with 345 revision.
Also alittle off topic but I just installed mima system and have been playing some. Has anyone noticed once battery is at one bar or even zero bars it is nearly impossible to hold lean burn at any constant speed in any gear even with background charging off completely.
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